Genetic variation affects morphological retinal phenotypes extracted from UK Biobank optical coherence tomography images

Optical Coherence Tomography (OCT) enables non-invasive imaging of the retina and is often used to diagnose and manage multiple ophthalmic diseases including glaucoma. We present the first large-scale quantitative genome-wide association study of inner retinal morphology using phenotypes derived from OCT images of 31,434 UK Biobank participants. We identify 46 loci associated with thickness of the retinal nerve fibre layer or ganglion cell inner plexiform layer. Only one of these loci has previously been associated with glaucoma, and Mendelian randomisation confirms that inner retinal thickness, despite being a valid biomarker for the disease, is not on the same genetic causal pathway as glaucoma. Image analysis methods were used to extract overall retinal thickness at the fovea, representative of hypoplasia, with which three out of the 46 SNPs were associated. These SNPs have been previously linked with pigmentation, confirmed by their association with hair colour in the UK Biobank dataset. We additionally associate these three loci with visual acuity. In contrast to the already known Mendelian causes of severe foveal hypoplasia, our results suggest a previously unknown spectrum of foveal hypoplasia in the population, in part genetically determined, that has consequences on visual function.